Just some thoughts based on those I have met in my life, but I have not parented a teen...
It sounds to me from what little information has been posted that she has a serious self esteem issue. I say this for a number of reasons but the expensive gifts are a huge red flag, particularly when she doesn't spend on herself. Psychiatrists like to say it is a manifestation of a subconscious feeling of being unworthy of the other person.
The comments from her that others are unworthy due to flaws in them may have less to do with perfectionism and judgmental behavior than self protection. If I reject someone else first, I don't need to worry that they will reject me. I must subconsciously determine a reason to reject them that fits withhow I want to be perceived.
The adoration from teachers and coaches suggests people pleaser, which is not inconsistent with low self esteem. Her strong desire for awards and recognition support both, particularly when considered along with the observation from teachers that she is humble and from you that she is driven to study.
It sounds to me right now like the studying is her vehicle now for escapism. Unless addressed, if I am right, this could easily change when she is older to boys or alcohol. Neither is pretty.
I do not think any of it is your fault. People pleasers by nature do not complain much. To do so would go against her idea of what a daughter "should" do or be.
My advice. Tell her you love her and compliment her to excess, if she truly seems humble. Recognize that whatever she is telling you about life is not likely 100% accurate, but is shaded by how she wants to be perceived by you (and herself). Ask her why she is so driven and what she hopes will come of it. Ask her if she wants to be homeschooled and what she would study if 100% free to choose. The answers, whatever they are, are likely to show you a better idea of what is going on in her head. (If she is a true people pleaser with low self esteem, you would never know if she is not challenged enough.)
